The Democratic governor said that while the bill's goal was laudable, its price tag was too high.

"Maintaining the quality and affordability of child care is a very important goal. So too is making sure that working conditions are decent and fair for those who take care of our children," Brown wrote in his veto message.

"Today California, like the nation itself, is facing huge budget challenges. Given that reality, I am reluctant to embark on a program of this magnitude and potential cost."

About half of California's estimated 80,000 child-care providers would have been affected by the legislation, which applied only to those workers within state programs subsidizing a family's child-care costs.

The ability to organize child-care workers has been a long-time goal of the state's major public employee unions -- the American Federation of State, County and Municipal Employees and the Service Employees International Union, which already represents many of the state's in-home caregivers.

Similar measures were vetoed three times previously by former Governor Arnold Schwarzenegger, a Republican.

Brown signed another budget-related measure on Tuesday allowing nonprofits to operate state parks, a strategy aimed at preventing the slated closure of some 70 parks in 2012 because of budget cuts.

SACRAMENTO, Calif. California Gov. Jerry Brown, saying no to the organized labor groups that helped elect him, vetoed a bill on Tuesday to allow some child-care workers to unionize.The Democratic governor said that while the bill's goal was laudable, its price tag was...